Textile products and methods of producing them



July 19, 1949. c. A. cAsTELLAN TEXTILE PRODUCTS AND METHODS 0F-PRODUCING THEM Filed Jan. 9, 1945 QSCJLLATOR 12E hse/Lum Masc/MTMINVENTOR.

Patented July 19, 1949 TEXTILE PRODUCTS AND METHODS F PBODUCIN G THEMCarl A. Castellan, Wilmington, Del., assignor to American ViscoseCorporation, Wilmington, Del., n. corporation of Delaware ApplicationJanuary 9, 1945, Serial No. 572,076

3 Claims. 1

This invention relates to improved textile products, and methods andapparatus for producing them, ofthe type which consist of or comprisepotentially adhesive fibers, some of which are bonded to adjacent fibersby virtue of coalescence induced by heating.

It has heretofore been suggested to mix nonadhesive fibers withthermoplastic fibers, to fabricate the mixture into a textile, such as aknotted, Woven, braided. netted, or knitted fabric, spun or continuousfilament yarn, felts or papers, and the-like, and either during or afterfabrication of the mixed fibers, to set the structure of the fabric byheating. In utilizing the conventional arrangements for heating suchproducts, diiiiculties arise in obtaining uniform activation of thethermoplastic. fibers within the mass. particularly when the fabric isheavy and thick, such as pile fabrics, coarse woven fabries, thick feltsand heavy papers, such as cardboard. When applying heated surfaces tothe surfaces of the textile product, the activation of the innerportions of the product is retarded by the resistance to heat transferafforded by the portions of the fabric intervening between the centralportion and the heating surfaces. In addition, the exposed potentiallyadhesive fibers `at the surface of the product which contact with theheating surfaces tend to stick to such surfaces and when the productafter activation is removed, it is frequently torn and disruptedadjacent the points of sticking. Even when applying internal heat bymeans of high frequency induction, the exposed thermoplastic bers havethe opportunity of stcking to whatever surfaces upon which the productmay rest, or between which it may be held during such activation.

In accordance with the present invention, the textile product issupported in contact with one or more cooled surfaces, while it is beingheated internally by high frequency induction, either inductively orcapacitatively coupled therewith. By thus applying the heat, thoroughactivation of the interior of the product is obtained, while at the sametime, the thermoplastic iibers in the surfaces of the product areprevented in one or both surfaces from attaining their fusion areactivatable by heat, or it may comprise such fibers with non-adhesiveilbers. Again, it may comprise a mixture of two types of thermoplasticbers, one of which has a lower tacklng point than the other type.

Examples of potentially adhesive fibers are those of cellulose acetateor other cellulose esters and ethers or mixed esters, such as celluloseacetate propionate or cellulose acetate butyrate, in

plasticized condition; also, resins, either perma,

nently thermoplastic or thermosetting but in the thermoplastic state,formed by the polymerization or condensation of various organiccompounds such as coumarone, indene or related hydrocarbons,polyethylene, vinyl compounds, styrene, sterols, phenol-aldehyde, resinseither unmodified or modified with oils, urea-aldehyde resins,sulfonamide-aldehyde resins, polyhydric alcohol-polybasic acid resins,drying oil-modified alkyd resins, resins formed from acrylic acid, itshomologues and their derivatives, sulfuroleflne resins, resins formedfrom dicarboxylic acids and diamines (nylon type); synthetic rubbers andrubber substitutes, herein called resins, such for example aspolymerized butadiene, olefine polysulildes, iso-butvlene polymers.chloroprene polymers; and fibers formed from a resin comprisingr theproduct of co-polymerizing two or more resins, such as copolymers ofvinyl halide and vinyl acetate, co-polymers of vinyl halide and .anacrylic acid derivative, and also a mixture of resins, such as a mixtureof vinyl resins and acrylic acid resins or. methacrylic acid resins, amixture of polyoleiine resins and phenol-aldehyde resins, or a mixtureof two orl more resins from the different classes just named. There maybe employed also fibers made from rubber latex, crepe rubber, guttapercha, balata, and the like.

Further, the potentially adhcsive'flbers may be mixtures of thecellulose derivatives with resins (c) An element-convertible resin(which be- A comes infusible through the action of certain elements,such as oxygen and sulfur, such for example as glycerol-polybasicacid-drying oil resins and cleflne-sulfur resins. Y

Among` the non-adhesive nlaments which may be used are wood pulp ilbers,cotton, flax, jute, kapok, silk, and the like, or synthetic filaments ofcellulosic compositions, such as a cellulose or regenerated cellulose,cellulose derivatives, such as cellulose esters, mixed cellulose esters,cellulose ethers, mixed cellulose ester-ethers, mixed cellulose ethers,cellulose hydroxy-ethers, cellulose carboxy-ethers, celluloseether-Xanthates, cellulose xanthofatty acids, cellulose thiourethanes;natural and synthetic rubber and derivatives thereof; alginic acid,gelatine, casein; mineral filaments such as spun glass, asbestos,mineral wool and the like; filaments made of natural and syntheticresins which should be of such type that they are not rendered tackywhen the potentially adhesive filaments are rendered tacky by heating;and the filaments made by slitting, cutting or shredding non-fibrousfilms, such as waste cellophane.

The drawing illustrates various arrangements of apparatus foraccomplishing the invention.

Figure 1 is a transverse cross-section in elevation of one embodiment,

Figure 2 is a cross-section in elevation partly in cross-section of amodification,

Figure 3 is a side elevation of the embodiment of Figure 2, and

Figure 4 is a side elevation of the third embodiment.

Figure l illustrates a batch method with thev electrodes in crosssection. The textile product 2, whether a fabric, felt-like, orpaper-like, is supported between two opposed flat-surfaced electrodes 3and 4 at a predetermined pressure of compaction. One pole of the radiofrequency oscillator is connected to the electrode 3 and the other poleis connected to electrode 4. The electrodes are hollow and the cavities5 receive a cooling fluid introduced by pipes 6 and discharged throughpipes 1. As a cooling medium, a gas, such as air, oxygen or nitrogen atany desired low temperature may be used. Alternatively, liquefied air orliquefied gases may be used. If desired. water, alcohol, hydrocarbons inliquid form andthe like may be used. Preferably the liquid thecontinuous travel and activation of a product of indefinite length.

.Figure 4 shows a m'odincation utilizing an electromagnetic field, theinduction coil 20 being connected to the opposite poles of an alternator2| and a hollow narrow platform 22 being disposed approximately with itsupper surface centrally of the coil. Cooling medium is introducedthrough the connection 23 and removed from the hollow platform by thepipe connection 24. A yarn or narrow strip of fabric, felt-like orpaper- 'like material is carried from the supply reel 25 over the topsurface of the supporting platform l22 on to the take-up reel 28. Theinternal diameter of the coil 20 may be varied widely to accommodatestrips of textile product of various widths.

The fabricating procedure may be of various types depending upon theparticular product desired. Depending upon the particular type ofproduct, it may be desired to apply the high frequency electric orelectromagnetic eld at different stages in the fabricating procedure andin some cases at a plurality of distinct stages in any one particularfabricating procedure. Thus, in the preparation of a woven or knittedfabric from a mixture of the potentially adhesive lilathat is used isone which does not tend to ionize Ldrums are adapted to be driven bymeans of a :pulley I4. Inlet pipes IS and outlet pipes I6 extendingvthrough opposite trunnions of the drums serve to introduce anddischarge the cooling medium. .In this embodiment, the connectionbetween the electrodes and the leads from ments with non-adhesivefilaments, the two types of filaments may be mixed upon a picker or cardand may then be subjected to drafting and spinning for producing a yarn.Such yarn'may be subjected to the heating effect of the high freuuencvelectric or electromagnetic field prior to fabrication into the finalfabric. Alternatively, the heat-activation may be deferred untilweaving, knitting, braiding or other fabricating operation has beencompleted so that the heat-activation serves not only to more or lessstabilize the structure of the yarns within the fabric but also tostabilize the structure of the fabric as a-whole by adhesion of thelaments at points of intercrossing of the weft and warp or of the loopsin the knitted fabric. Another alternative procedure is to activate theyarns prior to fabrication and to activate after fabrication. Such aprocedure would be of special advantage where it is desired to impart anincreased stiffness to the yarns within a fabric without a proportionalincrease in the adhesion between yarns forming the structure of thefabric. Such activation may be accompanied by a compacting pressure bycooled surfaces, if desired, and where the fabric being subjected to theelectric ileld is positioned between opposed substantially parallelplates used as electrodes having suitable insulating coatings bearingagainst the fabric, the pressure may be exerted against the fabric bythe electrodes themselves, the electrodes being cooled.

The invention is applicable also to fabrics in which alternating yarnsmay consist entirely of non-adhesive filaments and the other yarnstherein may comprise or may consist entirely of potentially adhesivefilaments activatable by heat. Besides mixing filaments of relativelyshort lengths such as staple fibers in the manner contemplated by thedescriptions hereinabove, the yarns may be formed of continuousfilaments some or all of which are activatable by heat and suchactivatable yarns may be fabricated by knitting, weaving, braiding,netting, or knotting in the same manner as a staple fiber yarn. Here,again, the activation may be effected upon the yarn prior tofabrication; activation'may be performed after fabrication; oractivation may be performed both after and before fabrication to thepoles of the oscillator may be accomplished textile products. The mixingof the continuous by brushes I1. This arrangement provides for filamentsof nonadhesive nature with those ananas which are heat-activatable maybe performed at the initial stage of filament formation where it is amatter of artificially producing the filaments. Alternatively, naturalor artificial continuous filaments of non-adhesive nature may becombined with natural or artificial continuous filaments ofheat-activatable nature by withdrawing untwisted filaments of the twotypes from suitable packages thereofand winding and twisting themsimultaneously upon a third common suitable package.

Pile fabrics may be produced from yarns composed of or comprisingas apart thereof heatactivatable filaments' either of continuous or shortlength nature and, as in other fabric constructions, the weft, warp andpile yarns may be of identical or entirely distinct composition and, asin the case of other fabrics, the yarns may be activated prior to thefabrication or the pile fabrics may be formed of, un-activated yarns oractivated yarns and subsequently subjected to effect activation thereof.

For the production of felt-type fabrics, such as textile felts, papers,paper and pulp products, such as cardboards, the mixtures of the twotypes of filaments may be effected by carding or by beating the twotypes of filaments together in a. suitable liquid suspension.Alternatively, the filaments may .be blown together in a vessel andallow to deposit by gravity upon a travelling conveyor such as a beltand, in this procedure, the filaments thus thrown into the vessel may beproduced in situ at that time by spraying or electrostatic methods. Thefelt-like sheet thus produced may be sub- `jected to an electrostaticfield between cooled insulated electrodes which may be pressed togetheragainst the sheet with any desired amount of pressure, as in Figure l.

The filamentous product being subjected to the electric field may bepassedcontinuously between insulated electrodes as in Figures 2 and 3,orvit may be passed over a cooling support (as 22 of Figure 4) orbetween two such cooling supports as it passes through anelectromagnetic field, or it may be held stationary during suchtreatment.` Alternatively, the yarn, cord, fabric,

and the like may be cut into pieces and formed l into a pile which issubjected to the electric or electromagnetic field. Again, the yarns orfab-l rics may be wound upon themselves into a package in which formstreatment may be effected.

Prior to subjection to the high frequency electric or electromagneticfield, the products to be treated may be impregnated or coated with anydesired agent for the purpose of imparting a desired finish, hand,pliability or appearance to the final product.

Any suitable high frequency oscillator may be -the particular frequencyemployed in any particular case depending upon the allowable voltage andthe amount of power desired. As stated hereinabove, pressure may beapplied to the filamentous product while it is being subjected to thehigh frequency electric field and such pressure may advantageously beapplied through the medium of the electrodes themselves, such electrodesbeing `insulated in such case, or it may be applied by the coolingsupporting surfaces. While the application of pressure is by no meansnecessary, it generally serves to more reliably and effectively controlthe extent of adherence between the adhesive 5 and non-adhesivefilaments in the product. Whereas the application of the activation heatby means of the ordinary procedures of radiation, convection andconduction has tended to give rise to glazed surfaces and non-uniformheating throughout the body of the mass, the use of the high frequencyelectric field for generating heat within the body of the individualfilaments of dielectric losses therein completely eliminates thisdifficulty.

During the stage of activation, the fabric may be manipulated in such away as to modify its dimensions and to reduce residual shrinkages in theproducts. For example, a, fabric comprising yarns, all of which containa major proportion of filaments composed of a copolymer of vinylchloride and vinyl acetate which has been produced with a stretch 'maybe subjected to a high frequency electric field and brought to such acondition whereby-as to cause the yarns to tend to shrink strongly byrelease of internal molecular forces. During such activation, the sizeof the fabric may be altered by allowing such shrinkage to occur to acontrolled extent to obtain the predetermined dimensions.

After activation, the fibers may be de-activated by cooling. This may beaccomplished merely by interrupting the supply of radio frequency powerto the electrodes in the case of the electrostatic arrangements ofFigures 1 to 3, or by interrupting the alternating current in thearrangement of Figure 4. Alternatively, the textile structure may beremoved from between the electrodes or from within the high frequencycoil and cooled outside their influence.

Textile fabrics, whether knitted or woven, braided or piled,' can thusbe produced which are substantially free of any tendency of thecomponent yarns and filaments therein to slip with respect to the othersthereby causing the fabric to stretch undesirably. This is particularlyimportant in knitted fabrics, which are thus made free of any tendencyto run or ladder upon the breakage of one of the loops therein. It ispossible to control slippage and laddering to any predetermined extentby adjusting the extent of activation. Fabrics thus stabilized byactivation of the yarns thereof may be characterized by the same highporosity and fullness of hand as such fabrics before such stabilization.

Depending upon the particular desideratum in the final fabric to beproduced, the percentage of 4 activatable filaments therein may bevaried widely. For simple stabilization of the fabric, a 60 range ofactivatable fibers between 5 to 25% of the entire weight of the fabricis generally adequate, the balance being non-activatable. Whenconsiderable stiffening of the fabric is also desired, higherpercentages up to 100% of activat- 65 able fiber may be present in thefabric.

By the invention, it is possible to activate the interior portions ofthe textile products to effect stabilization thereof by the bonding offibers therein without at the same time bonding fibers 70 in the facesof the fabric. In this manner, by controlling the cooling effect of thesurfaces in contact with the product in relation to the heating effectthereupon, a preferred handle and porosity may be present in the surfacelayers, re-

75 gardless of the proportion of potentially adhesive umass bers in theproduct, while at the same time any degree of activation of the berswithin the interior of the structure can be accomplished to stabilizethe structure either by merely bonding the bers without loss of beridentity, or to render an interior layer of the fabric substantiallyimpermeable by causing the bers therein to flow freely and thereby forma film through which the non-adhesive bers extend. Stabilization of theinterior of the structure may be accomplished by heating only suicientlyto soften the thermo plastic bers enough to cause them to shrink and tobecome deformed about the non-adhesive bers without actually becomingadhesively bonded thereto. Again any degree of activation between theextremes stated can be accomplished to obtain various properties in theproduct.

The present invention may be applied in the production of braids, felts,threads, or cords, for

usefas packing material and gasket material forl sealing relativelymoving or stationary parts of machinery of any kind, or in similar formas wicks for transmitting liquids to elements or surfaces to belubricated or otherwise coated. IThe invention may also be applied forthe production of felt-type products for making hats or other textileproducts or for use as battery separators, heat-insulation material,sound-insulation material, cushioning, padding, or as ltering materialseither for gaseous or liquid suspensions, etc.

The description herein is intended to be illustrative only and it is tobe understood that changes and variations may be made withoutdeparting-from the spirit and scope of the invention as dened by theappended claims.

I claim:

1. A method of making brous products comprising the steps of fabricatinga mass of bers comprising potentially adhesive heat-activatable bersinto a product having the activatable bers distributed generallythroughout the product, continuously passing the product through a pathbetween the nip of a pair of cooled rotors and inducing internal heatingof such product as it passes between the rotors by a high frequencycurrent passed therethrough to render the activatable bers adhesive tobind fibers in the body of the product while cooling the surfaces of theproduct to prevent the development of adhesiveness in theflbers whichlie in, and in close proximity to, the surfaces.

* A. P. C. case.

2. A method in accordance with claim 1 in which a. mixture ofnon-adhesive bers `and potentially adhesive bers are fabricated into'afelt. like mass. A

3. As an article of manufacture, a felt-like product formed from a matcomprising a mixture of non-adhesive and potentially adhesiveheat-activatable bers distributed generally throughout the product, theactivatable bers being generally homogeneously distributed throughoutthe thickness of the mat at least some of said bers in the body of theproduct exhibiting a strong and substantially permanent adhesion due tothe thermal tackiness after heating thereof, and those portions of saidbers which lie in, and in close proximity to, the surfaces of theproduct being unadhered.

' CARL A. CASTELLAN.

REFERENCES CITED The following references are of record in the NumberName Date Re. 22,320 Boeddinghaus May 25, 1943 229,798 Baseler May 11,1943 2,156,455 Kleine May 2, 1939 2,181,043 Boeddinghaus Nov. 21, 19392,231,457 Stephen Feb. 11, v1941 2,252,999 Wallach Aug. 19, 19412,253,000 Francis Aug. 19, 1941 2,278,895 Rugeley Apr. 7, 1942 2,303,983Brown Dec. 1, 1942 2,313,058 Francis Mar. 9, 1943 1 2,313,104 WallachMar. 9, 1943 2,319,809 Francis May 25, 1943 2,319,834 Wallach May 25,1943 2,324,068 Crandeii July 13, 194s 2,336,797 Maxwell Dec. 14, 19432,354,714 Strickland Aug. 1, 1944 2,390,266 Novotny Dec. 4, 19452,402,609 Brabander June 25, 1946 2,417,453 Wade Mar. 18, 1947 2,421,334Kline May 27, 194

OTHER REFERENCES Girdler Corp. publication, "Thermex High FrequencyHeating, copyright 1942, pages 9 to 11.

